Once again, many of North Texas' top-ranked public schools are some of its most selective, while others educate few students from low-income families, according to an annual ranking of North Texas schools.

Magnet schools such as Dallas ISD's School for the Talented and Gifted, Irma Rangel Young Women's Leadership School and Booker T. Washington High School for the Performing and Visual Arts crowd the top spots in this year's high school rankings by Children at Risk, a Houston-based education advocacy group.

They're followed by schools such as Liberty High School in Frisco ISD and Highland Park High School, which serves zero students from low-income families, according to Children at Risk.

"Any school that can be selective of the most talented and gifted, if they're not No. 1 in the state, then there's got to be a question there," said Robert Sanborn, president and CEO of Children at Risk. "Our focus from the beginning has been, let's highlight public schools. And if you're a magnet and selective, you're still a public school."

The group researched and ranked nearly 2,000 schools in nine North Texas counties, grading elementary and middle schools on an A-F scale based on STAAR reading and math test scores. It also considered growth made by students in those areas and adjusted achievement indicators to eliminate bias toward schools with few students from low-income families.

High school grades are based on STAAR scores, along with graduation rates and scores and participation rates on the SAT, ACT, Advanced Placement and International Baccalaureate exams.

The top schools will be recognized at a news conference at 10 a.m. Monday at Dallas ISD's School for the Talented and Gifted, 1201 E. Eighth St. in Dallas.

As in the past, high schools with a significant number of students from low-income families tended to remain at the bottom. Among them are South Oak Cliff High School, which has more than 92 percent economically disadvantaged students, and Eastern Hills High in Fort Worth ISD, the study's lowest-ranking North Texas high school with nearly 68 percent economically disadvantaged students.

"As a researcher, the best indicator of academic performance, unfortunately, is affluence," Sanborn said. "By and large, if you're a poor kid in Texas, and you want to go to a good school, you have to go to a magnet school or a high-performing charter. There's practically no options for you to go to a neighborhood school for high school."

But there are outliers. In a separate ranking, the organization highlighted high-performing, high-poverty elementary, middle and high schools. Among high schools in North Texas, there were only three — all Dallas ISD schools earning a B+ or B. The list also includes 91 elementary schools with five Dallas ISD schools ranking at the top and five middle schools.

"A couple years ago ... when we would look at Dallas ISD, much like most of the state of Texas, we didn't really see any high-performing, high-poverty schools," Sanborn said, crediting the shift possibly to principal changes and full-day prekindergarten.